diff --git a/wp-includes/default-filters.php b/wp-includes/default-filters.php
index 8663196248..5b312b54f1 100644
--- a/wp-includes/default-filters.php
+++ b/wp-includes/default-filters.php
@@ -246,7 +246,18 @@ add_filter( 'wp_robots', 'wp_robots_noindex_search' );
 add_filter( 'wp_robots', 'wp_robots_max_image_preview_large' );
 
 // Mark site as no longer fresh.
-foreach ( array( 'publish_post', 'publish_page', 'wp_ajax_save-widget', 'wp_ajax_widgets-order', 'customize_save_after' ) as $action ) {
+foreach (
+	array(
+		'publish_post',
+		'publish_page',
+		'wp_ajax_save-widget',
+		'wp_ajax_widgets-order',
+		'customize_save_after',
+		'rest_after_save_widget',
+		'rest_delete_widget',
+		'rest_save_sidebar',
+	) as $action
+) {
 	add_action( $action, '_delete_option_fresh_site', 0 );
 }
 
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-sidebars-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-sidebars-controller.php
index 7011018a83..3c1a83f0db 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-sidebars-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-sidebars-controller.php
@@ -209,6 +209,15 @@ class WP_REST_Sidebars_Controller extends WP_REST_Controller {
 
 		$sidebar = $this->get_sidebar( $request['id'] );
 
+		/**
+		 * Fires after a sidebar is updated via the REST API.
+		 *
+		 * @since 5.8.0
+		 * @param array           $sidebar  The updated sidebar.
+		 * @param WP_REST_Request $request  Request object.
+		 */
+		do_action( 'rest_save_sidebar', $sidebar, $request );
+
 		return $this->prepare_item_for_response( $sidebar, $request );
 	}
 
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php
index 899317fc8b..35cd9b4f94 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php
@@ -186,7 +186,7 @@ class WP_REST_Widgets_Controller extends WP_REST_Controller {
 	public function create_item( $request ) {
 		$sidebar_id = $request['sidebar'];
 
-		$widget_id = $this->save_widget( $request );
+		$widget_id = $this->save_widget( $request, $sidebar_id );
 
 		if ( is_wp_error( $widget_id ) ) {
 			return $widget_id;
@@ -248,7 +248,7 @@ class WP_REST_Widgets_Controller extends WP_REST_Controller {
 			$request->has_param( 'instance' ) ||
 			$request->has_param( 'form_data' )
 		) {
-			$maybe_error = $this->save_widget( $request );
+			$maybe_error = $this->save_widget( $request, $sidebar_id );
 			if ( is_wp_error( $maybe_error ) ) {
 				return $maybe_error;
 			}
@@ -356,6 +356,17 @@ class WP_REST_Widgets_Controller extends WP_REST_Controller {
 			);
 		}
 
+		/**
+		 * Fires after a widget is deleted via the REST API.
+		 *
+		 * @since 5.8.0
+		 * @param string           $widget_id  ID of the widget marked for deletion.
+		 * @param string           $sidebar_id ID of the sidebar the widget was deleted from.
+		 * @param WP_REST_Response $response   The response data.
+		 * @param WP_REST_Request  $request    The request sent to the API.
+		 */
+		do_action( 'rest_delete_widget', $widget_id, $sidebar_id, $response, $request );
+
 		return $response;
 	}
 
@@ -385,11 +396,12 @@ class WP_REST_Widgets_Controller extends WP_REST_Controller {
 	 *
 	 * @since 5.8.0
 	 *
-	 * @param WP_REST_Request $request Full details about the request.
+	 * @param WP_REST_Request $request    Full details about the request.
+	 * @param string          $sidebar_id ID of the sidebar the widget belongs to.
 	 *
 	 * @return string|WP_Error The saved widget ID.
 	 */
-	protected function save_widget( $request ) {
+	protected function save_widget( $request, $sidebar_id ) {
 		global $wp_widget_factory, $wp_registered_widget_updates;
 
 		require_once ABSPATH . 'wp-admin/includes/widgets.php'; // For next_widget_id_number().
@@ -401,12 +413,14 @@ class WP_REST_Widgets_Controller extends WP_REST_Controller {
 			$id_base       = $parsed_id['id_base'];
 			$number        = isset( $parsed_id['number'] ) ? $parsed_id['number'] : null;
 			$widget_object = $wp_widget_factory->get_widget_object( $id_base );
+			$creating      = false;
 		} elseif ( $request['id_base'] ) {
 			// Saving a new widget.
 			$id_base       = $request['id_base'];
 			$widget_object = $wp_widget_factory->get_widget_object( $id_base );
 			$number        = $widget_object ? next_widget_id_number( $id_base ) : null;
 			$id            = $widget_object ? $id_base . '-' . $number : $id_base;
+			$creating      = true;
 		} else {
 			return new WP_Error(
 				'rest_invalid_widget',
@@ -502,6 +516,17 @@ class WP_REST_Widgets_Controller extends WP_REST_Controller {
 			$widget_object->updated = false;
 		}
 
+		/**
+		 * Fires after a widget is created or updated via the REST API.
+		 *
+		 * @since 5.8.0
+		 * @param string          $id         ID of the widget being saved.
+		 * @param string          $sidebar_id ID of the sidebar containing the widget being saved.
+		 * @param WP_REST_Request $request    Request object.
+		 * @param bool            $creating   True when creating a widget, false when updating.
+		 */
+		do_action( 'rest_after_save_widget', $id, $sidebar_id, $request, $creating );
+
 		return $id;
 	}
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index ad58e267a2..7b0f934718 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-51067';
+$wp_version = '5.8-alpha-51068';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.